Concrete saws are used in a variety of applications including, but not limited to, scoring and cutting concrete in buildings. In order to be used in a building, the concrete saw must be able to pass through an entry door. This places practical limitations on the width of the concrete saw.
The cutting blade of a concrete saw is driven by a rotating blade shaft. In some concrete saws, the motor is axially aligned, meaning that the motor shaft rotates on an axis that is parallel to the axis of rotation of the blade shaft. Power can be transferred from the motor shaft to the blade shaft using V-belts and sheaves. The speed at which the blade shaft rotates can be adjusted by changing the size of the V-belts and sheaves.
As noted, there are practical width limitations for concrete saws. This limits the size of the motor when the motor is axially aligned. In order to accommodate the use of larger motors, it is often necessary to align the motor longitudinally, meaning that the motor shaft rotates about an axis that is perpendicular to the axis of rotation of the blade shaft. Conventionally, a bevel gear is used to transfer power from the motor shaft to a transverse drive shaft, which is oriented such that the drive shaft rotates about an axis that is parallel to the axis of rotation of the blade shaft. Thus, V-belts and sheaves can be used to transfer power from the drive shaft to the blade shaft. This arrangement, while satisfactory, presents several undesirable problems.
First, in this configuration the V-belts and sheaves are exposed to debris from the concrete cutting operation. This tends to shorten the life of the V-belts. Second, the V-belts must be removed periodically in order to adjust the rotational speed of the blade. This takes time and requires that the motor drive shaft be incrementally rotated in order to align the V-belts into engagement with the sheaves. Third, because the sheaves are installed on the blade shaft, the size of the sheaves is somewhat limited. Accordingly, a need exists for a concrete saw drive configuration that avoids or remedies one or more of these problems.
Belts have long been used to transfer rotary power between components. As is well known, it is often necessary to adjust the tension of a belt to prevent slippage or loss of engagement between the belt and a sheave or other component. For concrete saws using axially oriented motors, a wide array of belt tensioning assemblies are known. However, for a longitudinally oriented motor or engine, adjusting the distance between the belt driven components is more difficult. Accordingly, it would be desirable to provide a drive configuration for a concrete saw utilizing a longitudinally oriented motor in which the tension of the V-belts could be readily adjusted. As the size of a concrete saw increases, it becomes extremely heavy and difficult to manually maneuver. This is particularly so for assemblies that raise or lower the saw to effect a change in blade cutting depth. Thus, extendable hydraulic cylinders are typically used to facilitate such raising or lowering.
It is difficult to repeatedly and consistently achieve a desired blade cutting depth, particularly for large saws using hydraulically operated or assisted lifting or lowering assemblies. Current practice involves an operator selectively starting and stopping a control circuit for the hydraulic assembly until a desired blade depth is reached. Although this practice may be satisfactory, if the saw is repeatedly raised or the cutting depth is changed, this practice becomes burdensome. Accordingly, it would be desirable to provide a system for readily adjusting blade depth, and also returning to a preselected blade depth.
Walk-behind concrete saws include a pair of pivotally adjustable handles extending from their rear. The handles can be pivoted about a mounting assembly such that the outwardly extending handle ends can be pivoted upwards. The handle configuration is often preferred by operators when the front end of the saw, i.e. carrying the blade, is raised and the saw tilted rearwardly. Numerous mechanical arrangements are known for locking the handles in a desired position. However, eventually the assemblies wear, become loose and/or susceptible to fracture. Accordingly, it would be desirable to provide a concrete saw with an improved handle adjusting and locking system.
Prior to and during cutting operations, a flow of water is typically provided alongside the blade and/or cutting area. The water serves to cool the blade, reduce dust, and provide lubrication along the cut interface. Although currently known concrete saws include a variety of valves for stopping the flow of water, usually an operator must attend to this. In many instances, it is not necessary to provide a water stream at the blade, such as when not cutting or when the blade is in a raised position. Forgetting to stop the flow of water when not needed results in waste and excessive wear on the components of the water circuit. Accordingly, a need exists for a system for controlling water supply to a concrete saw cutting blade.